Jet propulsion plant



March 18, 1952 R. J. IMBERT JET PROPULSION PLANT 2 SHEETSSHEET 1 FiledMarch 19, 1947 n I disig-nce A -Frg5 95am mam IN l/eNTo R a C w e Md emwro 3 K m m o m 8 s c141 i nder he March is, 1952 R. J. IMBERT2,589,548 JET PROPULSION PLANT Filed March 19, 1947 2 SHEETS-SHEET 2' INVQN'TO R Patented Mar. 18, 1952 UNITED PATENT OFFICE .JETBROPULSIONPLANT "Rogerflejan t lmbert, Paris, France, assignor to S'ociete iBa'teau (Societe Anony ne), Paris, 1=rane, a pompany of France and 'ReneAnxionnaz 'Paris, :France, jointly ApplicationfMarch 19, 1Qg1 7 erialNo.735,676

. In r nna- 9 'CIa m (onto-eas In the prior U. S. Patent2,396,911'ofwhicnIjam one of the applicants, and relatinggto jet.propulsion plants for aircraft, there is describeda plant in which thecylinders of an internal combustion reciprocating engine driving theaircompressor are cooled by the flow of "air passing through the propulsionnozzle. The output of air reguire'd'ior propelling purposes issubstantially higher than the amount of air which isv sufficient forensuring this cooling. It is thereforenecessary to improve theefliciency of the propeller by limiting the output of the cooling air toitsoptimum value. The arrangements which are capable of, ensuring alimitation of this flow and improving'the cooling conditions of theengine form theobject of the U. S. application Serial No. 643,02sfiledby Marcel Sdille on January 24,1946, forimprover nents in ReactionPropellers. Inthis application, the flow of air delivered by thecompressor is divided into two parts of which one is projected towardsthe periphery and enters the-propulsion nozzle directly while thesecond, separated from the former bya suitable partitioning, issubmitted to the action of a booster or fan which is-tomake up for theloss of pressure inthe cooling circuit and this second air flow passesthrough; the compartment occupied by the cylinders et'the engine andensures the cooling; thereof.

My present invention has'for its object animprovement in the arrangementdiscl'osedhereinabove based on the separation-betweenfthe two flows, butit simplifies the arrangement by doing away with theauxiliary fanandensures a'greater adaptability in theoperation-of the plant.

The arrangementaccording. to-my invention also includes apartitionseparating the two flows,

.Fig, ti-illustrates a combinationof the adjustjment of the output andof the coolingflow and of the adjustment of the outer flow.

shows in partial cross-section, on an enlargedscale, the manner in whichthedeviceof Fig. 4 may be controlled.

Fig. 6 illustrates a temperature measuring .device positioned in theengine.

Tnthe first arrangement, Fig. 1 shows .at can aircompressor and at c thereciprocating .engine which drives saidcompressor. The air delivered bythe compressor is divided into two .cseparate flowsby a-partition bfsaidpartition extending in this case up to the propulsion nozzle.

The inner flow is ledby the partitionito the engine c for coolingthesame. .The outerflow is led directly to the propulsion nozzle.

' 'In;the figure, the cooling flow receives past the 'enginecthe exhaustgases-from the said engine 20.

-c but these gases might as wellbe discharged intothe outer flow. Itwill be noted that it is possibleto heat the outer flow throughtheagency {of the combustion chambers e and to heat the inner-flowthrough burners .12 arranged :between the engine and the propulsionnozzle.

The adjustment of the cooling flow is obtained by "a movable obturatoror throttle memberj of 'suitableout'line adapted to moveaxially so as tomodify theoutputcrossesectionof the nozzle D2 ;of the-cooling'circuit.This throttle member is shown :in its maximum :opening position in :the

upper half of the cross-section and -in.its throttling position in itslower half .cross-section The translational movement of this throttle.:member':-is ensured through any known means but with an extensionthereof toa point-at which the drop in pressure in the two-circuitsbecomes equal and it also allows usingainovable member adapted to modifythe outputof the cooling-flow in accordance with thetemperature of theengine.

The following description and corresponding accompanying drawing givenby way of example and by no means in alimitative: sense will allow abetter understanding of :my invention.

In said drawing:

Fig. 1 is a diagrammatic axial .crossasectionzof a propeller executed inaccordance with my invention and incorporating meansioradjusting thecooling flow at the output-of the. propeller.

Fig. 2 is a diagrammaticaxial. cross-sectional view of a modification oftheadjusting means-for adjusting the cooling flow.

Fig. 3 is a diagram showing the positions of the adjusting memberillustrated Fig, 2 correponding to qu libriumb tween o both gaseousflows.

such'asapiston g controlledin its turn by a dis- .tributorfihrundertheaction .of a thermostatk ac- .tuatedby the temperature of adelicatepart of the enginesuch as a'valve seat. ;Any other form pf :execu'tionmay -be., adopt e d as well.

This adjustment allows for instance keeping .:substantially constant theengine coolingcurrent spiteoiany variation in the-drop of pressure in thoute ircuit, which sirp inp e ma vary-accordingto therate o fgheating-of the outer flow through the combustion-performed at theburners e,-

Thi allows the ef r ma nta nin at su tab values the temperature of theengine and this latter variable factor may be used as disclosedhereinabpve asa base for the adjustment obtained with the obturator f,

Another possible embodimentoi my invention is shown in Fig. 2. In thiscase, the free crosssection area for the cooling fiownis vnot modifiedas in .the jpreceding case, but the point atwhich this coolingflow-mi'xes with the outer flow isdisplaced inside the expansion nozzleor in other words the pressure prevailing in the outlet of the coolingflow is modified to vary the output of cooling flow in accordance withthe value of the said pressure;

The arrangement allowing this variable condition assumes for instancethe shape of a cylindrical ferrule l adapted to move inside the exhaustnozzle with a translational movement and to this purpose the partition mends with a cylindrical part m1 serving as a guide for the ferrule I.

In Fig. 2 the exhaust or of. the engine is connected with the chamberused for the outer flow, but it may as well open into the cooling flowdownstream of the engine as in the case of Fig l.

The desired balance of pressure in the mixing cross-section of the twogasiform flows of the arrangement illustrated in Fig. 2 is checked bymeans of the graph of Fig. 3; starting from a static pressure prevailingat point 1. corresponding to the entrance of the air at A into theplant, .I obtain a pressure a at the output of the last wheel of thecompressor. The pressure curve for the outer flow, illustrated by thecurve 0 when said flow has not been heated, rises up to point 1 byreason of a slowing down effect in the channel following said last wheelafter which it slopes downwardly until it reaches the point 11. wherethe static pressure is equal to the ambient pressure and correspondingto the output end of the propulsion nozzle. When the outer flow includesmeans for heating through combustion by means of burners e, the curvefollows the dotted outline o1 underneath the line 0 precedinglyconsidered by reason of an increase of the speed of flow.

. The pressure curve of the cooling flow is shown at T when no heatingof this flow is provided and at 1-1 when the flow is submitted to aheating through a combustion operatedby the burners d.

The corresponding curves of the outer flow and of the cooling flow crossone another at four points: 12, x, y, 2 which define the respectivepositions to be occupied by the adjusting ferrule I, when the pressuresof both flows at the mixing point are to be maintained equal, accordingto the rate of running of the plant. Of course, for a suitable positionof the ferrule Z, it is possible, however, to have, at the mixing point,in the outer flow a pressure greater or smaller than that of the coolingflow and to vary in this manner the output of the cooling flow.

In my copending application Serial Number 643,027 filed on January 24,1946, now Patent No. 2,557,435, for Regulating devices for the outletsection of a reaction propeller tube or nozzle, I have described atelescopic nozzle adapted to move axially with reference to the reactionnozzle. Fig. 4 shows how it is possible with such a nozzle to associatethe adjustment of the position of the output nozzle of the cooling flowof gasiform fluid with the reduction in cross-section of the outputnozzle of the outer flow, said association giving a still greateradaptability to the operation of the propulsion plant.

In this case, it is possible to use the movable ferrule Z of Fig. 2, butthe latter instead of sliding directly inside the cylindrical end m1 ofthe partition separating the gasiform flows is carried hollow rod 92 ofwhich slides on the rod of piston inside an intermediary ferrule 15rigid with a nozzle u executed in accordance with the arrangementdisclosed in the last mentioned application referred to hereinabove.

This arrangement allows obtaining the extreme positions shown in thelower and higher crosssections, and also any intermediary .positioribegwhile the pressure fluid valve therefor is at in; said valve may beactuated in any manner, for example by hand.

What I claim is:

1. In a jet propulsion plant of the type comprising air compressionmeans having at least one compression stage, an internal combustionreciprocating engine driving said air compressing means, and apropulsion nozzle fed by said air compressing means for producing themotive jet; an annular partition beginning at the de-- livery side ofthe said air compressing means after the last compressing stage of saidair compressing means for dividing the air delivered by the lastcompression stage into two separate flows, one of which is led insidesaid partition around the engine for cooling the same, and the other ofwhich is by-passed outside of said partition towards the propulsionnozzle, said partition having a discharge end near the propulsionnozzle, heating means outside of said partition between the said laststage and the discharge end of the partition for heating said secondmentioned flow, and means near the discharge end of said partition forregulating the cooling flow inside said partition.

2. The combination of claim 1, wherein heating means are provided in thecooling flow between the engine and the end of said partition.

3. The combination of claim 1, wherein the regulating means for thecooling flow comprises a movable throttling member for varying theoutput of the cooling flow.

4. The combination of claim 1 comprising further temperature sensitivemeans arranged in the vicinity of the valves of the said engine, theregulating means for the cooling flow being controlled by saidtemperature sensitive means.

5. In a jet propulsion plant of the type comprising air compressingmeans having at least one compression stage, an internal combustionreciprocating engine driving said means, and a propulsion nozzle fed bysaid compressing means for producing the motive jet; a partitionbeginning at the delivery side of the said compressing means after thelast compression stage thereof for dividing .the air delivered by saidstage into two separate flows, one of which is led inside said partitionaround the engine for cooling the same, and the other of which isby-passed outside said partition towards the propulsion nozzle, saidpartition having a discharge end near the propulsion nozzle, heatingmeans provided in the outer by-passed flow as well as in the coolingflow between the engine and the discharge end of the partition and amovable throttling member arranged near the discharge end of the saidpartition for varying'the output of the cooling flow inside saidpartition.

'6. In a jet propulsion plant of the type comprising air compressingmeans having at least one compression stage, an internal combustionreciprocating engine driving said air compressing means, and apropulsion nozzle fed by said air compressing means for producing themotive jet; an annular partition beginning at the delivery side of thesaid air compressing means after the last compression stage for dividingthe air delivered by the last compression stage into two separate flows,one of which is led inside said partition around the engine for coolingthe same, and the other of which is by-passed outside said partitiontowards the propulsion nozzle, said partition having a discharge endahead of the propulsion nozzle, heating means outside of said partitionfor heating the second mentioned flow, and a movable ring at thedischarge end of said partition for variably prolonging the same towardsthe propulsion nozzle, said ring having a diameter less than that of theoutlet port of said nozzle, so that an annular passage for the outerby-passed flow remains open between said rin and said nozzle for eachposition of said ring.

7. The combination of claim 6, wherein heating means are also providedin thecooling flow between the engine and the end of said partition.

8. The combination of claim 6, wherein the movable ring comprises atleast two parts annular 25 telescopically arranged, one of saidparts'having further an annular nozzle adapted to cooperate 6 with thepropulsion nozzle for varying the crosssection area thereof.

9. The combination of claim 6, comprising further temperature sensitivemeans arranged in the vicinity of the valves of the said engine, thedisplacement of the said movable wall being controlled by saidtemperature sensitive means.

ROGER JEAN IMBERT.

REFERENCES CITED The following references are of record in the file ofthis patent: V

UNITED :STATES PATENTS Number Name Date 2,129,826 Dintilhac Sept. 13,1938 2,150,143 Adams Mar. 14, 1939 2,396,911 Anxionnaz et a1. Mar. 19,1946 2,407,719 Melchior Sept. 17, 1946 2,455,385 Scha i rer Dec. 7, 19482,458,600 Imbertet a1 Jan. 11, 1949 FOREIGN PATENTS Number Country Date844,442 France Apr. 24, 1939

